Mopidy is also a major building block in the
Pi Musicbox integrated
audio jukebox system for Raspberry Pi.

Mopidy is hackable

Mopidy's extension support and Python, JSON-RPC,
and JavaScript APIs makes Mopidy perfect for building your own
hacks.

In this example project, a Raspberry Pi is embedded
in an old cassette player. The buttons and volume control are wired
up with
GPIO
on the Raspberry Pi, and is used to control playback through a
custom Mopidy extension. The cassettes have
NFC
tags used to select playlists from Spotify.